Sidney Lumet's first effort as a film director, 12 Angry Men
is an adaptation of the 1954 Studio One television series episode of the same name and covers the deliberations of a jury at the trial of a young man from the slums for premeditated murder.
The film begins with the presiding judge giving instructions to the jurors, reminding them that the verdict must be unanimous, that the sentence in case of a guilt will be capital punishment, and that they must be absolutely certain of the defendant's guilt or deem him not guilty if they have reasonable doubts. After deliberations start, what first seemed to be an open and shut case of blatant guilt becomes more complicated when a lone juror emits doubts about the defendants guilt and discomfort with making a quick decision. The twelve jurors then find themselves having to re-examine whether the evidence is as strong as the prosecution made it out to be, how seriously they are taking their role in this process and whether personal prejudice stands in the way of reaching a fair verdict.
American Film Institute entry